| 摘要 |
<P>PROBLEM TO BE SOLVED: To realize an optical sensor with a small circuit scale capable of securing a high gain. <P>SOLUTION: An optical sensor 1 comprises a photodiode PD1, a dummy photodiode PD2, diodes D1, D2 converting output currents of the photodiode PD1 and the dummy photodiode PD2 into a voltage, and a differential amplifier for differential computing the converted voltage. The dummy photodiode PD2 is arranged at a position, at which a leak current of the photodiode PD1 is received, and is shielded from lights. The leak current flows to the dummy photodiode PD2, and an electric potential of the diode D2 is increased, and therefore, an electric potential difference between the photodiode PD1 side and the dummy photodiode PD side can be restrained, so as to restrain malfunction of the optical sensor 1. Also, when lights are incident on the photodiode PD1, a high gain can be obtained by the diode D1. Additionally, a characteristic can be improved without compensating the current, and therefore, a circuit scale does not increase. <P>COPYRIGHT: (C)2012,JPO&INPIT |
